There are many types of flow meters, and different flow meters have different requirements for specific application conditions. Common flowmeter application conditions are as follows.
1. Application conditions of positive displacement flowmeter
Common positive displacement flowmeters include oval gear flowmeters, scraper flowmeters, dual rotor flowmeters, rotary piston flowmeters, reciprocating piston flowmeters, disc flowmeters, liquid-sealed rotary drum flowmeters, wet gas flowmeters and membrane flowmeters gas meter, etc.
①The medium is clean and the viscosity is high;
② The measurement accuracy of the flowmeter is relatively high;
③ The turndown ratio is required to be less than 10:1;
④ Filters should be configured. For the measurement of a medium containing a small amount of gas, an air eliminator should be configured.
2. Application conditions of velocity flowmeter
Common velocity flowmeters include electromagnetic flowmeters, ultrasonic flowmeters, turbine flowmeters, vortex flowmeters, progression vortex flowmeters, rotor flowmeters, etc.
① For clean gas and liquid with low viscosity, a turbine or vortex flowmeter can be used;
② Turbine flowmeters can be used with higher accuracy requirements and a range ratio not greater than 10:1;
③ When the fluid viscosity is high, once it contains a small number of solid particles, the target flowmeter can be used;
④ For water, sewage and water-soluble wave fluids with electrical conductivity (conductivity greater than 10μS/cm), electromagnetic flowmeters and ultrasonic flowmeters can be used for fluids with corrosion resistance and wear resistance requirements;
⑤ When the medium is clean gas or liquid, and the Reynolds number is 200-1,000,000, differential pressure flowmeters, such as standard throttling devices, non-standard throttling devices, V-cone flowmeters, uniform velocity tube flowmeters, etc., can be selected. Wedge flowmeters can be used for measuring fluids with high viscosity and low flow rate (Reynolds number as low as 100) (such as residual oil, asphalt, etc.).
⑥ For small flow, the measurement accuracy is not higher than 1.5, and the turndown ratio is not more than 10:1, the rotor flowmeter (constant pressure drop flowmeter) can be selected.
3. Application conditions of mass flowmeter
①When it is necessary to directly and accurately measure the mass flow or density of the fluid, a mass flowmeter can be selected;
② When measuring the mass flow of the gas, the Coriolis mass flowmeter can be selected only when the gas density must be above 5kg/m3, otherwise the thermal mass flowmeter can be selected.